Precancerous Adenomas Research Articles

Abstract B102: Factors contributing to precancerous polyp detection in initial screening colonoscopies

Abstract Background: The incidence of colorectal cancer is persistently higher in Black/African Americans than other races in the United States. It is less clear whether Black/African Americans are at higher risk for colonic precancerous polyps, which represent an earlier stage in colorectal adenoma-carcinoma progression. Methods: A retrospective chart review was performed on initial average-risk screening colonoscopies on patients (age 45-75 years) during 2012 at 3 institutions. Multivariable logistic regression models were used to examine the relationship between potential risk factors and the detection of precancerous polyps. Results: Of the 2,225 initial screening colonoscopies, 1,495 (67.2%) were performed on Black/African Americans and 566 (25.4%) on Caucasian non-Hispanic patients. The mean age of initial colonoscopies was 57.1 y and 56.0 y for Black and Caucasian patients, respectively. Male patients represented 32.0% and 42.8% of the Black and Caucasian patients, respectively. Obese patients represented 41.4% and 31% of Black and Caucasian patients. A higher percentage (30%) of the Black patients were diagnosed with diabetes mellitus compared to Caucasians (11%). Multivariable logistic regression revealed that performance of the colonoscopy by academic gastroenterologists was associated with higher precancerous polyp detection compared to contractual nonacademic gastroenterologists (OR 1.69 95% CI 1.32-2.17, p<0.0001). Because of this observation, a physician feedback program was initiated, and as of 2017 the polyp detection rates at all three institutions reached 25%. In addition, multivariable analysis also identified older age (OR 1.03/year 95% CI 1,01-1,04 p= 0.0006), male sex (OR 1.60 95%CI 1.32-2.00 p<0.0001), current smoking (1.52 95% CI 1.32-2.17 p<0.0001) and diabetes mellitus (OR 1.27 95% CI 0.99-1.63 p = 0.062) as associated with higher precancerous colon polyp detection or adenoma detection rate (ADR). Neither race, ethnicity, BMI, nor insurance was significantly associated with detection rates. Conclusions: It is imperative that metrics of polyp detection rates be routinely monitored to ensure that all patients have access to high-quality screening colonoscopies. A prospective observational cohort study will help further identify factors associated with precancerous polyp detection, now that variations in operator detection rates have been addressed. Citation Format: Yakira David, Lorenzo Ottaviano, Jihye Park, Sadat Iqbal, Michelle Likhtshteyn, Samir Kumar, Helen Lyo, Ayanna Lewis, Brandon Lung, Jesse Frye, Li Huang, Ellen Li, Jie Yang, Laura Martello, Shivakumar Vignesh, Joshua Miller, Evan Grossman. Factors contributing to precancerous polyp detection in initial screening colonoscopies [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B102.

A sensitive and quantitative multimodal blood test for the detection of colorectal adenomas and cancer: Correlation with size and number of polyps.

1555 Background: Colonoscopic polypectomy is the primary reason for declining colorectal cancer incidence and mortality. Epidemiological evidence has ordered the timing and risk of pre-cancerous adenomas, localized and invasive cancer along a 7-10 year continuum. The increased size and number of index polyps are correlated with an increased probability of progression to cancer and informs surveillance colonoscopies. Methods: A single-center, IRB-approved, prospective, blinded study was conducted at the VA Palo Alto Health Care System. Results for 354 patients with no prior diagnosis of CRC who were scheduled for colonoscopy are presented. Indications for colonoscopy were 86% asymptomatic and 14% with symptoms or positive-FIT. Patients had blood drawn immediately prior to colonoscopy. The test analyzes three biomarkers: circulating gastrointestinal epithelial cells (CEC), validated somatic mutations, and methylation (SEPTIN9) of cell-free DNA and uses incident risk to calculate a CMx Score, scaled from 0 to 100. Multivariate regression methods were used to assess the degree of association between the pre-defined CMx Scores and polyp sizes and number, adjusting for both DNA mutation and DNA methylation status. Results: There is a significant association between CMx Scores and polyp size (F value = 5.80, p-value = 0.017). DNA mutation (F value = 1.29, p-value = 0.263) and methylation status (F value = 0.34, p-value = 0.560) were non-significant. Similarly, there is a significant association between CMx Scores and number of polyps (F value = 23.71, p-value < 0.0001). Again, DNA mutation (F value = 1.57, p-value = 0.210) and methylation status (F value = 1.34, p-value = 0.248) were non-significant. These results suggest that CMx Scores, which incorporate CEC, are providing predictive information of polyp sizes and number above and beyond DNA mutation and methylation status alone. Conclusions: A novel noninvasive multimodal blood-based assay that analyzes cell-free DNA for somatic mutations and methylation, CEC and integrates SEER incidence risk is significantly associated with polyp size and number. The opportunity to track progression and potentially inform colonoscopy interval is notable. [Table: see text]

Targeting cGMP/PKG signaling for the treatment or prevention of colorectal cancer with novel sulindac derivatives lacking cyclooxygenase inhibitory activity

Approximately 28 million people in the United States have precancerous colonic adenomas with many at high risk of developing colorectal cancer who could benefit from a pharmacological approach to prevent malignant progression. Clinical, epidemiological, and preclinical studies have reported or provided mechanistic evidence that nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce adenoma formation and the risk of developing colorectal cancer. Unfortunately, the long-term use of NSAIDs is not recommended because of potentially fatal toxicities resulting from cyclooxygenase (COX) inhibition and the depletion of physiologically important prostaglandins. However, multiple investigators have concluded that the mechanism responsible for the antineoplastic activity of NSAIDs does not require COX inhibition, which suggests the feasibility of developing safer and more efficacious derivatives for the treatment or prevention of colorectal cancer by targeting such mechanisms. We have widely reported that the NSAID, sulindac, inhibits certain phosphodiesterase (PDE) isozymes to increase intracellular cyclic guanosine monophosphate (cGMP) levels and activate protein kinase G (PKG) at concentrations that inhibit cancer cell growth in vitro. PDE5 and PDE10 are potential targets given that both are overexpressed in colon adenomas and adenocarcinomas and essential for colon cancer cell proliferation. An extensive medicinal chemistry campaign was conducted to identify novel sulindac derivatives lacking COX inhibitory activity with increased potency and selectivity to inhibit cancer cell growth. From a large collection of over 1500 compounds sharing the indene scaffold of sulindac, a series of derivatives were identified that inhibit cancer cell growth with high potency and selectivity by a mechanism involving the activation of cGMP/PKG signaling. Development candidates have been identified that block the oncogenic effects from APC gene mutations responsible for most human colorectal cancers by suppressing β-catenin-dependent transcriptional activity. This review describes the scientific rationale for the development of sulindac derivatives lacking COX inhibitory activity with improved potency and selectivity to inhibit PDE5 and/or PDE10 for the treatment or prevention of colorectal cancer.

Genomic and transcriptomic profiling of carcinogenesis in patients with familial adenomatous polyposis

ObjectiveFamilial adenomatous polyposis (FAP) is characterised by the development of hundreds to thousands of adenomas at different evolutionary stages in the colon and rectum that will inevitably progress to adenocarcinomas...

Pathways of Colorectal Carcinogenesis

Colorectal cancer is a heterogeneous disease that develops via stepwise accumulation of well-characterized genetic and epigenetic alterations. We review the genetic changes associated with the development of precancerous colorectal adenomas and their progression to tumors, as well as the effects of defective DNA repair, chromosome instability, microsatellite instability, and alterations in the serrated pathway and DNA methylation. We provide insights into the different molecular subgroups of colorectal tumors that develop via each of these different mechanisms and their associations with patient outcomes.

Abstract 3864: A novel PDE10/β-catenin pathway inhibitor, MCI-030, for the treatment of colorectal cancer

Abstract Over 90% of colorectal cancers harbor mutations in β-catenin or pathway components (e.g. APC) that stabilize β-catenin, causing nuclear translocation and constitutive Tcf-mediated transcription of genes encoding proteins essential for the proliferation and survival of tumor cells. We recently reported that the cyclic nucleotide degrading phosphodiesterase (PDE) isozyme PDE10 is overexpressed in colorectal cancers relative to normal tissue. Its expression and enzymatic activity are essential for colon tumor cell growth, as evidenced by knockdown of PDE10 expression using siRNA or inhibition of enzyme activity using known inhibitors such as PF-2545920. PDE10 inhibition in tumor cells expressing high levels of PDE10 causes increased intracellular cGMP levels to activate PKG and phosphorylate β-catenin, which induces ubiquitination and proteasomal degradation to suppress nuclear translocation and Tcf transcriptional activity. Conversely, ectopic expression of PDE10 in normal colonocytes or precancerous adenoma cells causes increased levels of β-catenin and the expression of proteins (e.g. cyclin D and survivin) essential for the proliferation and survival of tumor cells. To identify novel antitumor PDE10 inhibitors, we screened a chemically diverse library of indenes for PDE10 and tumor cell growth inhibitory activity. Following extensive chemical optimization, MCI-030 emerged as a potent and selective inhibitor of tumor cell growth. Similar to PF-2545920, but with appreciably greater potency and tumor cell selectivity, MCI-030 inhibited colon tumor cell growth by activating cGMP/PKG signaling to phosphorylate and induce β-catenin degradation. MCI-030 also inhibited colon tumor cell spheroid formation and reduced spheroid size and growth at concentrations that inhibit PDE10. Oral administration of MCI-030 significantly inhibited colon tumor formation in the Apc+/min-FCCC mouse model without discernable toxicity. Importantly, unlike PDE10 inhibitors developed to cross the blood-brain barrier for the treatment of CNS disorders, MCI-030 lacks the sedation side effects. Together, these findings support preclinical development of MCI-030 for the treatment of colorectal cancer as a novel PDE10 inhibitor capable of selectively inhibiting the growth of tumors harboring β-catenin or APC mutations. Funding provided by NCI grants R01CA131378, R01CA148817, R01CA197147, and R01CA155638. Citation Format: Antonio B. Ward, Xi Chen, Jacob Valiyaveettil, Kevin Lee, Wen-Chi L. Chang, Yulia Maxuitenko, Veronica Ramirez-Alcantara, Kristy Berry, Luciana Madeira da Silva, Bing Zhu, Tyler Mattox, Michael R. Boyd, Adam B. Keeton, Margie L. Clapper, Harry S. Cooper, Gary A. Piazza. A novel PDE10/β-catenin pathway inhibitor, MCI-030, for the treatment of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3864.

Effectiveness of fibrin sealant as hemostatic technique in accelerating ESD-induced ulcer healing: a retrospective study.

Healing of gastric endoscopic submucosal dissection (ESD)-induced ulcer is critical for patient recovery. During ESD treatment, submucosal incisions are made with an electrosurgical knife to accomplish en bloc resections of superficial lesions. Nevertheless, excess electrocoagulation may decrease the blood supply of ESD-induced ulcer and delay the ulcer healing. The aim of this retrospective study was to evaluate the effectiveness of conservative electrocoagulation followed by porcine fibrin sealant (FS) as a wound microvessels-protective hemostatic technique in promoting the healing of ESD-induced ulcer. A total of 332 patients with early gastric cancer (EGCs), or gastric precancerous lesion and gastric adenoma were retrospectively analyzed. Propensity score matching was used to compensate for the differences in age, gender, tumor location, resected specimen area, and pathology. One-month ulcer healing rates and delayed bleeding were compared between two matched groups (combined hemostats group and electrocautery group). A total of 115 matched pairs were created after propensity score matching. There was no difference in tumor location, specimen surface area, tumor differentiation and invasion depth between groups. The completed healing rate 1month after ESD was 44.3% in combined hemostats group and 30.4% in electrocautery group (P = 0.004). There was no difference in delayed massive bleeding rate between two groups (P = 0.300). In addition, based on the multivariate regression analysis for ulcer healing rate, the use of FS (OR, 0.348, 95% CI 0.196 - 0.617, P = 0.000) and larger specimen size (OR, 2.640, 95% CI 2.015-3.458, P = 0.000) were associated with nonhealing ulcer 1month after ESD. Applying conservative electrocoagulation followed by porcine FS as a wound microvessels-protective hemostatic technique can promote ESD-induced ulcer healing without increasing delayed bleeding.

5-Hydroxymethylcytosine profiling from genomic and cell-free DNA for colorectal cancers patients.

5‐Hydroxymethylcytosine (5hmC) is a DNA modification that is generated by the oxidation of 5‐methylcytosine (5mC) in a reaction catalyzed by the ten‐eleven translocation (TET) family enzymes. It tends to mark gene activation and affects a spectrum of developmental and disease‐related biological processes. In this manuscript, we present a 5hmC selective chemical labelling technology (hmC‐Seal) to capture and sequence 5hmC‐containing DNA fragments with low input. We tested 10 tumour/adjacent colon cancer tissues and 10 tumour/healthy plasma samples. Furthermore, we tested if this methodology could generate the 5hmC differential genes among cancer patients, healthy controls and precancerous adenoma patients from plasma. Robust cancer‐specific epigenetic signatures were identified for colon cancers. The results show that 5hmC is mainly distributed in gene active regions. The results also indicate the potential application of 5hmC change signals in early stage of colon cancer, even show potential in the diagnosis of precancerous adenoma. We demonstrated the robustness of the 5hmC‐Seal method in tissue and cell‐free DNA (cfDNA) as potential biomarkers. Moreover, this study provides the potential value and feasibility of 5hmC‐Seal approach on colorectal cancer (CRC) early detection. We believe this strategy could be an effective liquid biopsy‐based diagnosis and a potential prognosis method for colon cancer using cfDNA.

Fusobacterium nucleatum promotes colorectal cancer by inducing Wnt/β-catenin modulator Annexin A1.

Fusobacterium nucleatum, a Gram-negative oral anaerobe, is a significant contributor to colorectal cancer. Using an invitro cancer progression model, we discover that F.nucleatum stimulates the growth of colorectal cancer cells without affecting the pre-cancerous adenoma cells. Annexin A1, a previously unrecognized modulator of Wnt/β-catenin signaling, is a key component through which F.nucleatum exerts its stimulatory effect. Annexin A1 is specifically expressed in proliferating colorectal cancer cells and involved in activation of Cyclin D1. Its expression level in colon cancer is a predictor of poor prognosis independent of cancer stage, grade, age, and sex. The FadA adhesin from F.nucleatum up-regulates Annexin A1 expression through E-cadherin. A positive feedback loop between FadA and Annexin A1 is identified in the cancerous cells, absent in the non-cancerous cells. We therefore propose a"two-hit" model in colorectal carcinogenesis, with somatic mutation(s) serving as the first hit, and F.nucleatum as the second hit exacerbating cancer progression after benign cells become cancerous. This model extends the "adenoma-carcinoma" model and identifies microbes such as F.nucleatum as cancer "facilitators".

ADR of ‘Average Risk’ Males Aged 45-50 and >50 Screening Population Are Equivalent

Introduction: The American Cancer Society recently released updated “qualified recommendations” on Colorectal screening, recommending to start screening at age 45 for average risk population. These recommendations came out as a response to the increasing rates of CRC among adults less an age 50. The goal of our study was to analyze the adenoma detection rates (ADR) among people less than age 50 based on indication, particularly in compared to those who underwent “early” colonoscopy for average risk. Methods: Colonoscopy quality data was collected prospectively at our single tertiary referral center from June 2012 to June 2018. Inclusion criteria for the current study included all colonoscopies in patients aged 20 - 49, excluding those with inflammatory bowel disease and indications that had less than 30 total procedures. Within this cohort, ADR was analyzed by indication for colonoscopy. Significance was determined via a two-tailed Fisher’s exact test. Results: 1393 colonoscopies met our inclusion criteria. Average age (SD) of patients was 38.8 years (8.4). A breakdown of indications for this group are shown in Table 1. Subgroup analysis showed that ADR of patients 45-50 years old getting colonoscopy for “average risk” was 0.39 (OR 0.87 95% CI 0.59 to 1.3), 0.28 for females and 0.46 for males. The ADR for our average risk population > age 50 in our database is also 0.46. Conclusion: We are in the early days of the new ACS recommendation. The USPSTF and GI societies will soon decide if new guidelines will lower the screening age for colonoscopy. In the setting of what can be a pivotal moment in CRC screening guidelines, we present data showing that the risk of having a precancerous adenoma in the average risk population is near that of the population we are currently screening, and in the case of males aged 45-50 the risk of a precancerous adenoma is equal to that of the established screening population, further warranting CRC screening for all people aged 45-50 years.228_A Figure 1. Indications and ADR for Colonoscopy in Patients < 50 years228_B Figure 2. ADR for Average Risk Patients aged 45-50 Compared to Average Risk age > 50

Comparison of cold and hot snaring polypectomy for small colorectal polyps: study protocol for a randomized controlled trial

BackgroundColorectal cancer remains a considerable challenge in healthcare nowadays. Most patients’ disease develops via the adenoma–carcinoma sequence; colonoscopy with polypectomy effectively reduces both mortality and incidence by removing precancerous adenomas. Previous studies showed that polypectomy without electrocautery (cold snaring polypectomy) is a safe and time-saving procedure to manage polyps < 10 mm. However, randomized controlled trials have failed to prove the superiority of cold snaring polypectomy for reducing the risk of delayed bleeding in comparison with hot snaring polypectomy, generally because of their low statistical power that was limited by sample sizes. In this study, we aim to compare the risk of delayed bleeding following cold and hot snaring polypectomy based on a large sample size.MethodsThis is a prospective multicentre randomized controlled trial to compare cold and hot snaring polypectomy for the treatment of small colorectal polyps. A total of 4258 patients with small polyps (4–10 mm) will be randomized 1:1 to each group. Colonoscopy and polypectomy will be performed by 17 experienced endoscopists at six study sites. The randomization will be performed via an online website. Pathological examination using image-enhanced endoscopy with either narrow-band imaging or chromoendoscopy will be conducted to confirm optically and histologically that complete resections have been achieved, respectively. The primary outcome measurement is the risk of delayed bleeding. The secondary outcome measurements include the number of hemoclip applications, complete eradication confirmed optically and histologically, tissue retrieval rate, procedure time, emergency unit visits, and any adverse events such as immediate bleeding or perforation.DiscussionWe hypothesize that cold snaring polypectomy can reduce the risk of delayed bleeding by avoiding thermal injury. In addition, this study will also compare cold and hot snaring polypectomy in terms of the complete eradication rate and procedure time. Based on data collected, we will demonstrate that cold snaring polypectomy is a safe, effective, and economic procedure for small colorectal polyps. The results will also provide additional data on which to develop recommendations for treating small colorectal polyps.Trial registrationClinicalTrials.gov, NCT03373136. Registered on 29 November 2017.

Abstract 1937: Inhibition of a novel cancer target, PDE10, suppresses Wnt/β-catenin signaling and colon tumorigenesis: Benefits from combining with ornithine decarboxylase inhibitors

Abstract Sulindac has been shown in clinical trials to reduce the number and size of precancerous colon adenomas, but is not recommended for the long-term management of polyposis syndromes because of potentially fatal toxicities resulting from cyclooxygenase (COX) inhibition and the suppression of prostaglandin synthesis. Here we characterize the activity of a non-COX inhibitory sulindac derivative, MCI-030, that inhibits a novel cancer target, phosphodiesterase 10A (PDE10), recently reported to be overexpressed in colon tumors and essential for tumor cell growth (Oncogene 34:1499-509, 2015). PDE10 is an attractive cancer target because of limited expression and no known function in normal peripheral tissues. MCI-030 potently and selectively inhibits the growth of multiple colon tumor cell lines expressing PDE10 with IC50 values of 0.3 μM, but does not affect the growth of normal colonocytes (NCM460) that do not express PDE10. Sulindac inhibits colon tumor cell growth with IC50 values approximately 200 fold higher and modest tumor cell selectivity. MCI-030 is PDE10 selective, but sulindac inhibits multiple PDE isozymes (PDE2, 3, 5, and 10). MCI-030 treatment of colon tumor cells increased intracellular cGMP levels and activated protein kinase G at concentrations that inhibit recombinant PDE10 and tumor cell growth. Inhibition of PDE10 by MCI-030 or siRNA increased the phosphorylation and degradation of β-catenin and inhibited Wnt-induced nuclear translocation to suppress TCF-mediated transcription of cyclin D and survivin, leading to cell cycle arrest and apoptosis. With attractive pharmacokinetics and ability to achieve high concentrations in colon mucosa following oral administration, MCI-030 was tested in the APC+/min-FCCC mouse model of colon tumorigenesis. At 7-8 weeks of age, mice endoscopically determined to be adenoma-free were assigned to receive either control or MCI-030 supplemented diet (1500ppm) for 14 weeks. MCI-030 reduced the multiplicity of colonic adenomas by 50% (control: 3.95 ± 0.81 vs. MCI-030: 1.95 ± 0.58, P &amp;lt; 0.05) and incidence by 36.7%. MCI-030 also reduced the multiplicity of polypoid adenomas (36%), microadenomas (69%), and flat adenomas (100%, P &amp;lt; 0.05). These data indicate that MCI-030 strongly inhibits tumorigenesis in a predictive preclinical mouse model of colorectal cancer without discernable toxicity and could be effective together with colonoscopy in humans to reduce polyp formation and prevent malignant progression. In addition, in vitro colony formation and transformation assays using human colon tumor cells showed benefits of combining MCI-030 with the ornithine decarboxylase inhibitor, DFMO, supporting testing of this novel combination in the APC+/min-FCCC mouse model as a strategy to further improve efficacy. Funding from NCI R01CA131378, R01CA148817, R01CA197147, and R01CA155638. Citation Format: Gary A. Piazza, Ashleigh Neese, Kevin Lee, Adam Keeton, Yulia Maxuitenko, Veronica Ramirez Alcantara, Kristy Berry, Jacob Valiyaveettil, Antonio Ward, Luciana Madeira da Silva, Jennifer Scalici, Bing Zhu, Tyler Mattox, Xi Chen, Margie Clapper, Harry Cooper, Wen-Chi Chang. Inhibition of a novel cancer target, PDE10, suppresses Wnt/β-catenin signaling and colon tumorigenesis: Benefits from combining with ornithine decarboxylase inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1937.

Identification of marker genes and pathways specific to precancerous duodenal adenomas and early stage adenocarcinomas.

The mechanism behind the pathogenesis and carcinogenesis of these neoplasms is not fully understood. The objective of this study was to identify genetic markers and pathways specific to precancerous duodenal adenomas and early stage adenocarcinomas through gene expression analysis. Gene expression profiling was performed in 4 pairs of duodenal adenoma/adenocarcinomas and corresponding matched normal tissue. Genes with consistent expression differences were identified and confirmed in 7 independent pairs. Gene set enrichment analysis (GSEA) was performed to characterize gene expression profiles of duodenal adenoma/adenocarcinomas, together with immunohistochemical staining of candidate oncogenic genes. 626 probes consistently demonstrated over a twofold expression difference between tumor-normal pairs. Reverse transcriptase polymerase chain reaction of genes with the most prominent difference in expression between tumors and normal mucosa (KLK7, KLK6, CEMIP, MMP7, KRT17, LGR5, G6PC, S100G, APOA1) validated the results of gene expression analysis. GSEA demonstrated a strong association between duodenal adenoma/adenocarcinomas with colorectal adenomas (p < 10-5) and gene expression patterns seen after APC gene knockout (p < 10-5), suggesting that the Wnt/β-catenin pathway plays a crucial role in the carcinogenesis of these neoplasms. Immunohistochemical staining of an independent group of duodenal adenomas confirmed over-accumulation of β-catenin in 80.0% (16/20). Precancerous duodenal adenomas and early stage adenocarcinomas demonstrate gene expression characteristics with a strong resemblance to colorectal adenomas. The results of this study strongly suggest that upregulation of the Wnt/β-catenin pathway is the major factor involved in the initial stages of the carcinogenesis of duodenal adenocarcinomas.

Mitotic polarization of transcription factors during asymmetric division establishes fate of forming cancer cells

A model of K-Ras-initiated lung cancer was used to follow the transition of precancerous adenoma to adenocarcinoma. In hypoxic, Tgf-β1-rich interiors of adenomas, we show that adenoma cells divide asymmetrically to produce cancer-generating cells highlighted by epithelial mesenchymal transition and a CD44/Zeb1 loop. In these cells, Zeb1 represses the Smad inhibitor Zeb2/Sip1, causing Pten loss and launching Tgf-β1 signaling that drives nuclear translocation of Yap1. Surprisingly, the nuclear polarization of transcription factors during mitosis establishes parent and daughter fates prior to cytokinesis in sequential asymmetric divisions that generate cancer cells from precancerous lesions. Mutation or knockdown of Zeb1 in the lung blocked the production of CD44hi, Zeb1hi cancer-generating cells from adenoma cells. A CD44/Zeb1 loop then initiates two-step transition of precancerous cells to cancer cells via a stable intermediate population of cancer-generating cells. We show these initial cancer-generating cells are independent of cancer stem cells generated in tumors by p53-regulated reprogramming of existing cancer cells.

Colonic Tubulovillous Adenoma With High-Grade Dysplasia and Pseudoinvasion: A Diagnostic Pitfall

Introduction: interpretation of histopathologic features of resected colonic polyps is critical to subsequent management. We are a presenting a case of colonic villous adenoma with pseudoinvasion /misplacement of epithelium (PEM) into the stalk mimicking invasive carcinoma. Such phenomenon can be unfamiliar to the gastroenterologist. Case: 56 y/o male, h/o diabetes and hypertension, referred for colon cancer screening. Patient has been asymptomatic. His physical examination was unremarkable. Colonoscopy revealed 1.5 cm polyp with short stalk polyp at the splenic flexure (figure 1), which was removed wit hot snare. Pathology was consistent with tubulovillous adenoma with focal high grade dysplasia and pseudoinvasion involving the cauterized margin, with misplaced epithelium, and rounded, displaced glands surrounded by lamina propria (Figure 1).Figure: MUCOSA WITH RELATED MUSCULARIS MUCOSA. THE MUCOSA IS HERNIATING INTO THE SUBMUCOSA PSEUDOINVASION LOW POWER VIEW.Discussion: Colon cancer is the second leading cause of cancer-related deaths in the United States (when men and women are combined). It is established that removing precancerous adenomas not only reduce the risk of colorectal cancer but also significantly reduce the deaths from the disease. The histopathological features of resected polyps impact on subsequent management. In this case, there was high grade dysplasia, and the adenomatous epithelium appeared misplaced into the stalk and as such mimicking invasive carcinoma (pseuodinvasion). There are no definite endoscopic or clinical features to differentiate between the two lesions, and diagnosis depends solely on pathologic findings. In pseudoinvasion, the displaced glands are cytologically similar to the overlying adenoma and are rounded, often admixed with nonadenomatous glands, and surrounded by normal lamina propria, and often hemosiderin is seen in lamina propria. These features are in contrast with those of an invasive mucinous carcinoma. Additional histological scrutiny along with histochemical staining was necessary to exclude invasive cancer. Pseud invasion may be the result of repeated twisting of the stalk causing hemorrhage and this facilitates the prolapse of non-malignant adenomatous epithelium through the muscularis mucosa. Conclusion: There is difficulty inherent in distinguishing between pseudoinvasion and invasive carcinoma. Awareness and recognition of pseudo-carcinomatous invasion in adenomatous polyps and its distinction from invasive cancer is critical for both subsequent treatment and appropriate reporting.

The Obese Patient: Effects of Split-dose Preparation During Colonoscopy on Adenoma Detection Rate

Introduction: Obesity is associated with an increased risk of colorectal cancer. A study by Grewal, et al showed that adenoma detection rate (ADR) is higher among overweight and obese males compared to their normal weight counterparts, suggesting a higher prevalence of precancerous adenomas in this population. ADR, however, is not a direct measure of adenoma prevalence because of its dependence on colonoscopy quality, including the quality of the bowel prep. Obesity is an independent risk factor for suboptimal bowel prep, suggesting that ADR may significantly underestimate adenoma prevalence in this group. Because split-dose bowel prep is associated with improved bowel prep scores, our aim was to determine if split-dose bowel prep is also associated with higher ADR among obese patients. Methods: This study utilized prospectively collected data at point-of-care using Qualoscopy (Docbot, Inc). Inclusion criteria was all obese patients, defined as a BMI ≥30, who had colonoscopies performed for any indication at our outpatient facilities from June, 2012 to April, 2017. Statistical analysis was performed using chi-square and two-sample t-test. For reference, the same measures were analyzed in normal/underweight (< 25) and overweight BMIs (25-29.9). Results: Of 1419 colonoscopies performed among obese patients, 856 (60.3%) received split-dose bowel prep and 563 (39.7%) received single-dose prep. The split-dose group was weighted towards female patients, but there were no significant differences in BMI, gender, or primary indication (table 1). ADR was significantly higher among those who received split-dose (50.7% vs 38.4%, p < 0.001). Similarly, adequate bowel prep (defined as a Boston Bowel Prep Score ≥8) was significantly more frequent in the splitdose compared to single-dose groups (72% vs 60%, p < 0.001). The degree of benefit of split-dose prep, as measured by % improvement in ADR and % improvement in fraction of adequate preps, was highest in obese patients compared to those who were normal/underweight or overweight (table 2).Table: Table. Patient DemographicsTable: Table. Outcomes Based on BMI and Bowel Preparation UsedConclusion: Our data shows that split-dose bowel prep in obese patients is associated with significantly higher ADR and percentage of patients with adequate prep. Furthermore, these benefits of split-dose prep were most pronounced among the obese population. Based on compelling evidence that higher ADRs are associated with lower interval cancer rates, our data supports widespread use of split-dose prep in this high-risk population.

Abstract 5243: Novel non-COX inhibitory sulindac derivative with β-catenin suppressing activity reduces the formation of colorectal adenomas and adenocarcinomas in the APC +/min-FCCC mouse model

Abstract Sulindac can reduce the number and size of precancerous colonic adenomas in patients with familial adenomatous polyposis (FAP), but is not recommended for long-term use as a cancer chemopreventive drug because of potentially fatal toxicities associated with cyclooxygenase (COX) inhibition. Here we characterize the antineoplastic properties of a novel sulindac derivative, ADT-061, that lacks COX-1 and COX-2 inhibitory activity. ADT-061 potently and selectively inhibited colon tumor cell growth in vitro with IC50 values of 0.3-0.5 μM by inducing apoptosis without affecting the growth of normal colonocytes at concentrations 100x higher. By comparison, sulindac sulfide (SS) inhibited colon tumor cell growth with IC50 values of 40-60 μM, and had only modest tumor cell selectivity. While SS non-selectively inhibits multiple cyclic GMP phosphodiesteraes (PDE) isozymes, previous studies have suggested an important role for PDE10 in colon cancer (Li et al, Oncogene, 2014; Lee et al, Oncotarget, 2015). At concentrations comparable to its IC50 values, ADT-061 selectively inhibits PDE10 to induce an increase in intracellular cGMP levels and activate protein kinase G (PKG). ADT-061 also suppressed nuclear levels of β-catenin and induced cell cycle arrest and apoptosis, within the same concentration range that inhibits tumor cell growth. With attractive drug-like properties, the chemopreventive activity ADT-061was assessed using the APC+/min-FCCC mouse model of spontaneous colorectal tumorigenesis. Prior to treatment, colonoscopy exams were performed on all APC+/min-FCCC mice (males, 6-7 weeks of age) to ensure the absence of colorectal adenomas. At 7-8 weeks of age, mice were assigned (19 per group) to receive either unsupplemented chow (control) or chow supplemented with ADT-061 (1500ppm) for 14 weeks. No discernible toxicity was observed during the experimental period. Double-blinded pathological analysis of fixed colon tissues revealed that ADT-061 not only reduced the multiplicity of colonic adenomas by 50% (Mean ± SEM, control vs. ADT-061, 3.95 ± 0.81 vs. 1.95 ± 0.58, P &amp;lt; 0.05), but also decreased the incidence of colonic adenomas by 36.7% (control vs. ADT-061, 94.7% vs. 57.9%, respectively). ADT-061 treatment reduced the multiplicity of polypoid adenomas (36%), flat adenomas (100%, P &amp;lt; 0.05), and microadenomas (69%). The formation of colonic adenocarcinomas found in 15.8% of untreated mice was completely inhibited in mice treated with ADT-061. These data indicate that ADT-061 inhibits colon tumorigenesis when given to APC+/min-FCCC mice prior to the detection of gross colonic tumors. These observations support further evaluation of ADT-061 and analogs for colorectal cancer chemoprevention. Citation Format: Kevin J. Lee, Xi Chen, Jacob Valiyaveettil, Ashley S. Lindsey, Joel Andrews, Veronica Ramirez-Alcantara, Adam B. Keeton, Gary A. Piazza, Harry Cooper, Margie Clapper, Wen-Chi L. Chang. Novel non-COX inhibitory sulindac derivative with β-catenin suppressing activity reduces the formation of colorectal adenomas and adenocarcinomas in the APC+/min-FCCC mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5243. doi:10.1158/1538-7445.AM2017-5243

Su1759 - Elucidating the Role of FIT and FOBT in Detecting Precancerous Colonic Adenomas in Initial Colonoscopies

Su1759 - Elucidating the Role of FIT and FOBT in Detecting Precancerous Colonic Adenomas in Initial Colonoscopies

Su1764 - Poorly Controlled Diabetes and Morbid Obesity Increase the Risk of Precancerous Colonic Adenoma Development in Initial Colonoscopies

Su1764 - Poorly Controlled Diabetes and Morbid Obesity Increase the Risk of Precancerous Colonic Adenoma Development in Initial Colonoscopies

LINE-1 is preferentially hypomethylated within adenomatous polyps in the presence of synchronous colorectal cancer

BackgroundConventional tubular adenomas are frequently detected in patients undergoing average risk screening colonoscopy and are over-represented in patients who will develop colorectal cancer (CRC). Whether features of adenomas could serve as predictors of synchronous CRC is not known. Here, we investigate whether global methylation markers, including LINE-1, differ within adenomas in patients with and without synchronous CRC.MethodsColorectal tubular/tubulovillous adenomatous polyps in the absence (P group, n = 45) and in the presence of synchronous CRC (PC group, n = 32) were identified. Global methylation and demethylation by ELISA for 5-methylcytosine (5-mC) and 5-hydroxymethyl cytosine (5-hmC), respectively, were assessed in polyps and adjacent normal non-neoplastic tissue. LINE-1 hypomethylation was assessed by pyrosequencing of bisulfite-converted DNA as well.ResultsGlobal methylation (5-mC) showed no differences in overall methylation status in the adenomatous polyps in the two groups (5-mC relative to control %, PC group 0.117; P group 0.161, p = 0.148). Global hydroxymethylation 5-hmC was also not significantly different in adenomatous polyps of the PC group than in those of the P group (0.0059 vs 0.0097, p = 0.681). Similarly, global 5-hmC was not different between normal tissues from patients without neoplasia in comparison to those from CRC patients (0.0461 ± 0.080 vs 0.039 ± 0.159, p = 0.215). In contrast, adenomatous polyps of the PC group had lower levels of LINE-1 methylation compared to the adenomas in the P group (53.07 ± 4.5 vs 59.95 ± 5.4, p < 0.001). LINE-1 methylation was also significantly lower in the normal tissue from cancer patients compared to that from patients without any neoplasia (58.07 ± 3.78 vs 71.50 ± 6.47, p < 0.001).ConclusionsLINE-1 hypomethylation of precancerous adenomas correlates with the presence of synchronous CRC. Measurement of DNA hypomethylation levels of colorectal adenomas by LINE-1 could have future implications in approaches to defining CRC risk in screening programs.